Migration covers a wide variety of activities in wildlife in the Highlands including in and around Inverness. The publicity last year of EJ, the ringed and named osprey at Loch Garten, caused quite a stir as once again it had returned to its nest site after the long haul of a few thousand miles to and from Africa. Later this spring the swifts will be screaming around their nest sites in Inverness and two of the colonies are, aptly, at the old Scottish Natural Heritage Offices at Culduthel Road and Ardconnell Terrace. On a different level the grey wagtails will return to their nest sites along rivers and burns after many had move south, perhaps only a few miles, or west to get away from the winter weather. Swallows and house martins will soon be back and the first of this family will almost certainly be the sand martins that nest in banks of rivers and burns.
Another form of migration, often called movements as they are much shorter, involves one of the more enigmatic animals of the Highlands namely the common toad. The migration of the toads, sometimes covering over a mile, started at the end of the breeding season last summer. The toads will have moved away from their sites in lochs, lochans and ponds. Unlike the common frog they cannot absorb enough oxygen through their skin to stay submerged in the water for any length of time. They move out and find crevices in stones, in the ground or under such things as logs and when the winter comes they hibernate there. Most of them will move to the same area so that large assemblies can gather. The weather, including cold and length of days, triggers them off and in the right conditions in the spring they may migrate over a period of hours.
This is where many of us will see them in and around Inverness as their route often takes them across roads. In the next few weeks it will not uncommon to see them moving across a road under cover of darkness, sometimes even during the day. If large numbers are involved over short periods many can be killed by vehicles in even one night. Predators will also capitalise on this abundance of food from buzzards to crows and otters to pine martens. In the urge to mate and fertilise the eggs as they emerge from the female toad there is often a frenzy of activity. Some more amorous males will climb on the back of a female as she is en route to the pond and hitch a ride the rest of the way. Once in the water there is another problem as sometimes so many males attend a single female that a large ball of toads may form. This takes place in the water and the unfortunate female may drown as she cannot get enough air.
Such was the case with the toads in the photograph that was taken last year on the sides of Loch Farr, just south of Inverness. This was in the shallows near the boathouse. It was adjacent to the road between Farr and Garbole and the colony may well be the largest anywhere in the Highlands. Reference books often say that toads generally breed in large, deep water bodies but this is not always the case. For example near Ardersier there is a fire pond on the edge of a forestry plantation. It only measures a few metres across and yet there is a colony of toads there that often goes completely un-noticed. There are two roads running immediately adjacent to the pond but there are few road casualties as the traffic is sparse.